This invention relates to soldering of electronic components.
In the fabrication of many types of electronic components, it is desirable to solder only localized areas without disturbing other components which may be mounted on the same circuit board. For example, one form of high performance connector uses a flexible circuit which is soldered to a completed circuit board (see, e.g., U.S. Pat. No. 4,806,107 issued to Arnold, et al). Further, in the assembly of printed circuit boards, repair of one or more components is often necessary, which involves a re-soldering of the repaired component. In addition, the mounting of selected surface-mounted components on the board is advantageously done by localized heating, especially when the component has a high number of I/O pins.
Some techniques for localized heating are presently available. For example, a hot ram can be used to solder a flexible circuit to a circuit board (see, e.g., Clark, et al, U.S. patent application Ser. No. 372,400, filed Jun. 27, 1989 and assigned to the present assignee). Such techniques may or may not provide sufficient heat regulation for sensitive components. Inductive heating has also been suggested, where a bus bar soldered to a board includes ferromagnetic pins with coils wrapped around the pins (see U.S. Pat. No. 4,795,870) or where the leads of a multipin component are coated with a ferromagnetic material and placed in the gap of a ferrite core (see U.S. Pat. No. 4,789,767). The ferromagnetic material has a Curie temperature which is chosen to provide self-regulated heating.
Other techniques, such as condensation soldering can be self-regulating, but cannot be applied locally. Even in the cases of prior inductive heating techniques, difficulty can be encounted in providing heat to pads which are made inaccessible by high I/O components.
It is, therefore, an object of the invention to provide an alternative method for selective soldering of electronic components.